/*
 * Copyright 2016 The Netty Project
 *
 * The Netty Project licenses this file to you under the Apache License,
 * version 2.0 (the "License"); you may not use this file except in compliance
 * with the License. You may obtain a copy of the License at:
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 * License for the specific language governing permissions and limitations
 * under the License.
 */
package io.netty.util.internal;

import java.io.IOException;
import java.net.InetAddress;
import java.net.InetSocketAddress;
import java.net.NetworkInterface;
import java.net.ServerSocket;
import java.net.Socket;
import java.net.SocketAddress;
import java.net.SocketException;
import java.net.SocketPermission;
import java.net.UnknownHostException;
import java.nio.channels.DatagramChannel;
import java.nio.channels.ServerSocketChannel;
import java.nio.channels.SocketChannel;
import java.security.AccessController;
import java.security.PrivilegedAction;
import java.security.PrivilegedActionException;
import java.security.PrivilegedExceptionAction;
import java.util.Enumeration;

/**
 * Provides socket operations with privileges enabled. This is necessary for
 * applications that use the {@link SecurityManager} to restrict
 * {@link SocketPermission} to their application. By asserting that these
 * operations are privileged, the operations can proceed even if some code in
 * the calling chain lacks the appropriate {@link SocketPermission}.
 */
public final class SocketUtils
{

    private SocketUtils()
    {
    }

    public static void connect(final Socket socket,
            final SocketAddress remoteAddress, final int timeout)
            throws IOException
    {
        try
        {
            AccessController.doPrivileged(new PrivilegedExceptionAction<Void>()
            {
                @Override
                public Void run() throws IOException
                {
                    socket.connect(remoteAddress, timeout);
                    return null;
                }
            });
        }
        catch (PrivilegedActionException e)
        {
            throw (IOException) e.getCause();
        }
    }

    public static void bind(final Socket socket, final SocketAddress bindpoint)
            throws IOException
    {
        try
        {
            AccessController.doPrivileged(new PrivilegedExceptionAction<Void>()
            {
                @Override
                public Void run() throws IOException
                {
                    socket.bind(bindpoint);
                    return null;
                }
            });
        }
        catch (PrivilegedActionException e)
        {
            throw (IOException) e.getCause();
        }
    }

    public static boolean connect(final SocketChannel socketChannel,
            final SocketAddress remoteAddress) throws IOException
    {
        try
        {
            return AccessController
                    .doPrivileged(new PrivilegedExceptionAction<Boolean>()
                    {
                        @Override
                        public Boolean run() throws IOException
                        {
                            return socketChannel.connect(remoteAddress);
                        }
                    });
        }
        catch (PrivilegedActionException e)
        {
            throw (IOException) e.getCause();
        }
    }

    public static void bind(final SocketChannel socketChannel,
            final SocketAddress address) throws IOException
    {
        try
        {
            AccessController.doPrivileged(new PrivilegedExceptionAction<Void>()
            {
                @Override
                public Void run() throws IOException
                {
                    socketChannel.bind(address);
                    return null;
                }
            });
        }
        catch (PrivilegedActionException e)
        {
            throw (IOException) e.getCause();
        }
    }

    public static SocketChannel accept(
            final ServerSocketChannel serverSocketChannel) throws IOException
    {
        try
        {
            return AccessController
                    .doPrivileged(new PrivilegedExceptionAction<SocketChannel>()
                    {
                        @Override
                        public SocketChannel run() throws IOException
                        {
                            return serverSocketChannel.accept();
                        }
                    });
        }
        catch (PrivilegedActionException e)
        {
            throw (IOException) e.getCause();
        }
    }

    public static void bind(final DatagramChannel networkChannel,
            final SocketAddress address) throws IOException
    {
        try
        {
            AccessController.doPrivileged(new PrivilegedExceptionAction<Void>()
            {
                @Override
                public Void run() throws IOException
                {
                    networkChannel.bind(address);
                    return null;
                }
            });
        }
        catch (PrivilegedActionException e)
        {
            throw (IOException) e.getCause();
        }
    }

    public static SocketAddress localSocketAddress(final ServerSocket socket)
    {
        return AccessController
                .doPrivileged(new PrivilegedAction<SocketAddress>()
                {
                    @Override
                    public SocketAddress run()
                    {
                        return socket.getLocalSocketAddress();
                    }
                });
    }

    public static InetAddress addressByName(final String hostname)
            throws UnknownHostException
    {
        try
        {
            return AccessController
                    .doPrivileged(new PrivilegedExceptionAction<InetAddress>()
                    {
                        @Override
                        public InetAddress run() throws UnknownHostException
                        {
                            return InetAddress.getByName(hostname);
                        }
                    });
        }
        catch (PrivilegedActionException e)
        {
            throw (UnknownHostException) e.getCause();
        }
    }

    public static InetAddress[] allAddressesByName(final String hostname)
            throws UnknownHostException
    {
        try
        {
            return AccessController
                    .doPrivileged(new PrivilegedExceptionAction<InetAddress[]>()
                    {
                        @Override
                        public InetAddress[] run() throws UnknownHostException
                        {
                            return InetAddress.getAllByName(hostname);
                        }
                    });
        }
        catch (PrivilegedActionException e)
        {
            throw (UnknownHostException) e.getCause();
        }
    }

    public static InetSocketAddress socketAddress(final String hostname,
            final int port)
    {
        return AccessController
                .doPrivileged(new PrivilegedAction<InetSocketAddress>()
                {
                    @Override
                    public InetSocketAddress run()
                    {
                        return new InetSocketAddress(hostname, port);
                    }
                });
    }

    public static Enumeration<InetAddress> addressesFromNetworkInterface(
            final NetworkInterface intf)
    {
        return AccessController
                .doPrivileged(new PrivilegedAction<Enumeration<InetAddress>>()
                {
                    @Override
                    public Enumeration<InetAddress> run()
                    {
                        return intf.getInetAddresses();
                    }
                });
    }

    public static InetAddress loopbackAddress()
    {
        return AccessController.doPrivileged(new PrivilegedAction<InetAddress>()
        {
            @Override
            public InetAddress run()
            {
                if (PlatformDependent.javaVersion() >= 7)
                {
                    return InetAddress.getLoopbackAddress();
                }
                try
                {
                    return InetAddress.getByName(null);
                }
                catch (UnknownHostException e)
                {
                    throw new IllegalStateException(e);
                }
            }
        });
    }

    public static byte[] hardwareAddressFromNetworkInterface(
            final NetworkInterface intf) throws SocketException
    {
        try
        {
            return AccessController
                    .doPrivileged(new PrivilegedExceptionAction<byte[]>()
                    {
                        @Override
                        public byte[] run() throws SocketException
                        {
                            return intf.getHardwareAddress();
                        }
                    });
        }
        catch (PrivilegedActionException e)
        {
            throw (SocketException) e.getCause();
        }
    }
}
